Drum



March 5, 1963 AGERMAN 3,080,131

' DRUM Filed Oct. 19, 1959 INVENTOR. Era k zqgerm an OM Q flffom ey.

nite i 3,080,131 DRUM Vasteras, Sweden, assignor to Allmanna Erik Agerman, s d

we en, a

This invention relates to improvements in drums and more particularly to an improved cable or rope drumfor mine hoists, although the invention is of course, not limited to the use of cables or ropes in mine hoists, as it is adapted for a wide range of utility.

in the construction of drums, pulleys or the like, it is of considerable importance to be able to reduce the weight of the construction as much as possible without reducing its loading capacity and thereby its mechanical strength.

In drum constructions previously known, a drum comprises a rim in the form of a cylindrical casing on which the cables or ropes run or are to be mounted. This casing is provided with two side walls in the form of plane discs through the centre of which passes a shaft, the axis of said shaft constituting the axis of rotation of the drum. As the drum is exposed to side forces, i.e. forces not lying in a plane vertical to the axis of rotation of the drum, the plane discs will to a certain degree act as membranes, and to eliminate the fiexures in these discs in the best possible way, the discs have to be given an undesired material thickness or be stiffened by ribs or the like, the drum construction thereby increasing in weight without an increase in mechanical strength for a certain load. In drum constructions which have passing shafts, the weight of the shaft itself will increase the weight of the drum per se.

The principal object of this invention is to provide an improved drum with a pronounced rigidity against side forces and without a passing shaft, the drum being in the form of a monocoque construction which allows a reduction of weight at least 39% compared with a conventional drum.

With these and other objects in view the invention consists in certain novel features of construction and combination, an arrangement of parts, as will be more fully described hereinafter and pointed out in the claims.

In the accompanying schematical drawing is shown a section view of the embodiment of the drum according to the invention.

Referring to the drawing, 1 denotes a cylindrical sheet casing to which are secured two side walls 2 and 3 in the form of stump angled cones, the cones welded to the said casing at their bases and the axis of rotation of the said casing coaxial with the geometrical axes of the cones. The said cones are positioned with their bases facing each other. 4 and 5 denote shaft pivots secured to the said cones 2 and 3 at their peaks, the axis of rotation of the said pivots being coaxial with that of the said sheet casing 1. The said pivots are journalled in bearings 6 and 7, the middle or centre lines 8 and 9 of which pass through the peaks 10 and i l of the cones or cross the cones between their peaks and bases. The broken lines 12 and 13 denote the middle contour lines of the walls of the cones. This said specific orienting of the bearing middle line in relation to the cone peak and base makes it possible to avoid undesired moment of flexure on the shaft pivots. The shaft pivot may constitute an integral part of a cone or be welded or riveted to a cone.

The sheet casing 1, together with the two conical side walls 2 and 3, defines the drum as a monocoque con- S atent struction which has a pronounced rigidity against side forces, and as the forces exerted in the cones comprise substantially tensile and compressive forces, the thickness of the conical side walls of the drum can be reduced without loosing their mechanical strength and rigidity. The reduced thickness of the walls and the elimination of a passing shaft, this said shaft being substituted by small shaft pivots 4 and 5, gives a light-weight drum compared with other conventional drums of the same mechanical strength.

The drum may be driven by a motor (not shown), the shaft end 14 of which may be coupled to one of said shaft pivots. To give the drum a certain flexibility without the possibility of transfer of forces from the drum to the motor shaft, a flexible coupling may be arranged between the shaft end of the motor and the shaft pivot in question.

By locating the distribution of forces in the side walls 2 and 3 of the drum, the side walls may be provided with apertures which further reduce the weight of [the drum.

The sheet casing 1 of the drum may be provided with cylindrical end portions 15 and 16, the said portions extending axially beyond the base of said cones 2 and 3 and the said end portions constituting braking areas or surfaces for radially movable brake shoes (not shown). As the brake shoes would transmit heavy forces to the Said end portions of the casing 1, it would be necessary to stiffen said portions 15 and 16. According to the invention sheet rings 17 and 18 are welded to the casing -1 and the side Walls 2 and 3, so that a triangular section is formed by the ring 17 or 18, the casing 1 and a side wall 2 or 3. If it should be desired to use brake shoes movable in the direction of the axis of rotation of the drum, the said casing 1 could be provided with a radially extending sheet ring, the brake shoes thereby pres-sing against the opposite side surfaces of said ring.

The cylindrical sheet casing 1 may itself be stiffened by one or more sheet rings 19.

In the embodiment of the drum shown in the drawing the drum is adapted as a driving rope drum for a mine hoist and the cylindrical sheet casing 1 carries backing rings 20 and 2d of friction material on which rings the ropes 2,2 and 23 are running.

Various light changes might be made in the general form and arrangement of parts described without departing from the scope of the invention, and hence it should not be limited to the precise detail set forth, but it must be considered allowable to make such changes and alterations as fairly fall within the spirit and scope of the appended claims.

I claim:

1. A drum structure comprising a cylindrical casing of sheet material, two truncated cones secured to said casing with their cone bases facing each other and spaced a substantial distance apart, stud shafts each having an external bearing surface adapted to be mounted in a bearing for carrying said drum, said cones being each secured at the apex to one of said stub shafts, said cones constituting the main support of said cylindrical casing, said drum having an interior free of any transverse shaft supporting said drum.

2. A drum structure as claimed in claim 1 in which the apex angles of said cones are obtuse.

3. In a drum structure as claimed in claim 1, said cylindrical casing having end portions extending axially beyond said cone bases, the central part of said cylindrical casing between said end portions being of greater axial length than said end portions.

4. A drum structure as claimed in claim 1, in which said external bearing surfaces are situated at least partly 3 v 4 between two planes through the apexesofls a idcpncs at References;Citedjnthe file of this patent right angles tdthaxis of saidbearing surfaces. 4 UNITED STATES i TENf 5. A drum structure asclaimedin claim- 1 in which the said casing comprises cylindrical end portions ex- 2 MFmtgomery 1890 tending axially beyond the bases of said cones, and stiff- 5 1509977 Mlnspaugh 1926 ening rings of sheet material secured to said end portions and to said cones at planes locatedbetween said stub E NPA E h 9,221 Great Britain v i '6; A drumstructure as claimed in claim 5 inwhich 2803.19? egg-B g d Q; f fi'jj' 'gjg said-stiffening rings are secured to said-cones nearer t0"101 2 8 8 ,O8 6 Germany Oct. 19,1 9 115 said coneb-ses than'tto; the apexes of said cones; 

1. A DRUM STRUCTURE COMPRISING A CYLINDRICAL CASING OF SHEET MATERIAL, TWO TRUNCATED CONES SECURED TO SAID CASING WITH THEIR CONE BASES FACING EACH OTHER AND SPACED A SUBSTANTIAL DISTANCE APART, STUD SHAFTS EACH HAVING AN EXTERNAL BEARING SURFACE ADAPTED TO THE MOUNTED IN A BEARING FOR CARRYING SAID DRUM, SAID CONES BEING EACH SECURED AT THE APEX TO ONE OF SAID STUB SHAFTS, SAID CONES CONSTITUTING THE MAIN SUPPORT OF SAID CYLINDRICAL CASING, SAID DRUM HAVING AN INTERIOR FREE OF ANY TRANSVERSE SHAFT SUPPORTING SAID DRUM. 